Ge-Based Photoreceivers for SWIR Sensing and Imaging - Journey Toward Single-Photon Detection (Invited)

Ge-based photoreceivers, widely applied in Si photonics (SiPh) for high-speed optical communication, have recently adventured into the territory of shortwave infrared (SWIR) sensing and imaging. Here I review the history and key milestones including the recent demonstrations of lock-in detection with Ge-in-Si and single-photon detection with Ge-on-Si.